build: use doc-only instead of doc

Use `make doc-only` instead of `make doc` where applicable.

PR-URL: https://github.com/nodejs/node/pull/16309


Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>